GABAergic Synapses

In article <30r5sl$g71 at portal.gmu.edu>,
HARRY R. ERWIN <herwin at mason1.gmu.edu> wrote:
>so. Walter Freeman indicates that no one who has studied the GABAergic
>synapse has investigated the effect of chloride concentration on its
>excitatory/inhibitory nature. Has there been any work done here? I'm
Barry Rhodes did his dissertation on the excitatory action
of GABA on the periglomerular cells in the olfactory bulb,
and another group (I don't have the
reference on me) imaged Cl- and found that the distribution of Chloride
in the olfactory bulb would also indicate that GABA has an
excitatory action on the periglomerular cells.
In the retina GABA has both actions
(or so I'm told), and Michaelson and Wong published some evidence that
GABA is both excitatory and inhibitory in the Hippocampus. The most
elementary thing one learns about neurotransmitters is that the action
depends on the receptors and on the ion gradients, not on the
neurotransmitter, but this is often ignored.
Leslie Kay
lmk2 at garnet.berkeley.edu